Another celebrity nearly got a royal diss from the Mile High Club. Surprisingly, it was flight safety — not sagging pants or “Flying While Fat” — that is at the center of the most recent uproar.

It looks like Whitney Houston is straight outta rehab and (as we say in the hood) straight up trippin’. But not because of crack (Thank goodness for small favors.). As TMZ puts it … she’s just crazy â€” and yesterday she almost got kicked off a Delta Airlines flight yesterday … because she refused to buckle her seatbelt.

Guess they don’t call her a “diva” for nothin’.

A bit of “drahmah” hit the Friendly Skies on Wednesday afternoon, after the Grammy-winning songbird initially refused to buckle up before taking off on a flight from Atlanta to Detroit, where she’s expected to begin filming on the movie remake Sparkle.

“…Whitney boarded a flight in Atlanta Wednesday afternoon … and when she settled into her seat, a crew member asked her to buckle up. We’re told Whitney refused and “got diva” on the crew member … until another crew member came over and warned Houston that if she didn’t buckle up, she would have to get off the plane. Whitney eventually allowed one of the crew members to grab the buckle and fasten it for the singer â€” and the plane was then cleared for takeoff. Sources close to the singer tell us … Whitney ‘overreacted a little bit after missing an earlier flight but she’s still 100% sober and was on the way to Detroit for her first day of shooting a new movie .'”

Other informants concur that Whit “wasn’t drunk, drinking or on drugs,” and was instead battling exhaustion. Eventually – after exchanging some heated words with a flight attendant – the 48-year-old pop star put on her seatbelt and the plane was able to take off.

This is the third time in recent months that a celeb has had trouble aboard a commercial flight: In September, Southwest Airlines revoked Green Day’s lead man Billie Joe Armstrong boarding pass for wearing saggy jeans. Armstrong was escorted off a plane after failing to follow a flight attendant’s directive to pull his pants up. And last year, the same airline removed portly director Kevin Smith from a flight for being “too fat” to properly fit into a single seat.